Truing tool for a grindstone

ABSTRACT

A truing tool for a grindstone ( 1 ) is intended for attachment to a universal support ( 3 ) in the form of a cylindrical rod of a grinding machine in parallel with the rotation axis of the grindstone. It has—in a holder ( 12 ) therefore—a cutting tip ( 13 ) for truing engagement with the grindstone. The holder ( 12 ) is movably connected to a yoke ( 10 )—to be attached to the universal support ( 3 )—by a feeding rod ( 14 ), which is rotatably supported by the yoke ( 10 ) and is in engagement with a threaded bore in the holder ( 12 ), for its movement in relation to the yoke transversely of the grindstone ( 1 ).

TECHNICAL FIELD

The present invention relates to a truing tool for a grindstone, the tool being intended for attachment to a universal support in the form of a cylindrical rod of a grinding machine in parallel with the rotation axis of the grindstone and having—in a holder therefore—a cutting tip for truing engagement with the grindstone.

BACKGROUND OF THE INVENTION

It is well known in the art that a grindstone rotating in a grinding machine needs truing every now and then, because its peripheral grinding surface, which should be round and planar, becomes worn and uneven by extensive use.

A presently used truing tool as defined in the first paragraph of the specification provides an acceptable truing result, but the result obtained depends at least partly on manual work of the operator, both with regard to the adjustment before truing and the truing itself.

Another drawback with this tool is that it comprises two separate parts, which may be lost and which makes the mounting on the machine more difficult.

THE INVENTION

The drawbacks with the known truing tool are obviated and a truing tool with simplified operation is according to the invention obtained in that the holder is movably connected to a yoke—which is attached to the universal support—by a threaded feeding rod, which is rotatably supported by the yoke and is in engagement with a threaded bore in the holder, for its movement in relation to the yoke transversely of the grindstone.

This feeding rod may according to the invention be provided with operating knobs at its ends outside the yoke.

The holder further has a transverse hole for its movable connection to the universal support. The important advantage obtained is that the holder will be guided by two “axles”, namely the universal support and the feeding rod, which adds to the stability and accuracy of the tool.

The cutting depth for the cutting tip is set by fine adjusting the height of the universal support over the grindstone.

THE DRAWINGS

The invention will be described in further detail below under reference to the accompanying drawings, in which

FIG. 1 is a perspective view of a known grindstone truing tool in use,

FIG. 2 is a front perspective view of a grindstone truing tool according to the invention,

FIG. 3 is a rear perspective view of the tool according to the invention and illustrates its mounting, and

FIG. 4 is a rear view of the tool according to the invention and illustrates its use at the truing of a grindstone.

DETAILED DESCRIPTION OF AN EMBODIMENT

A rotatable grindstone 1 of a grinding machine has to be trued at intervals in order to be kept fit for its intended purpose of grinding for example woodcarving tools.

A known truing tool for this purpose is illustrated in FIG. 1. The tool has a U-rod 2 to be slid on a universal support or cylindrical rod 3 attached on the grinding machine in parallel with the rotation axis of the grindstone 1. The U-rod 2 can be attached to the universal support 3 by means of two lock screws 4.

Also slid onto the universal support 3 between the two arms of the U-rod 2 is a holder 5, which has a through hole for the universal support. At its forward end, the holder is provided with a cutting tip 6, whereas the opposite end can be held against the U-rod 2.

The cutting tip 6 consists of diamond grains embedded in a copper cylinder. The grains are positioned like “raisins in a cake”. During use, the soft copper will be worn, and the diamond grains will stick out as peaks on the surface. Worn grains will after a period of time be replaced by new ones. This design gives a long life to the tip 6.

In use, the intended cutting depth of the tip 6 can be determined by the position of the U-rod 2 on the universal support 3. While the grindstone 1 is rotating, the holder 5 is held against the U-rod 2 and manually moved back and forth over the grindstone 1 for obtaining a smooth surface on the grindstone.

A truing tool according to the invention is shown in FIGS. 2-4.

The main constituent of the inventive truing tool is a plate-shaped yoke 10 with side edges having holes for mounting the tool on the universal support 3 of the grinding machine above the grindstone 1. The yoke 10 is provided with a fastening screw 11 at one of the side edges for its locking to the universal support 3.

The other side edge has two protrusions 10′ for guiding the yoke 10 in relation to a threaded leg 3′ of the universal support 3. With locking screws 16 on the grinding machine unlocked, the universal support 3 may be raised or lowered with high precision by means of an adjustment nut 3″, whereupon the locking screws 16 are again locked. The adjustment nut 3″ is preferably provided with measurement indexes.

A holder 12 having on its underside a cutting tip 13 of the same type as has been described above and with a through hole for sliding onto the universal support 3 is arranged under the yoke 10 between its side edges.

A threaded feeding rod 14, parallel with the universal support 3 and the rotation axis of the grindstone 1, is rotatably arranged in the side edges of the yoke 10. It is provided with an operating knob 15 at each end outside the side edge of the yoke 10. The threaded rod 14 extends through a threaded bore in the holder 12 or rather threaded bores in the side edges of the holder 12 with the result that the holder 12 with the cutting tip 13 may be transferred sideways sliding under the yoke by turning the knobs 15 (as is illustrated in FIG. 4).

The operation of the described truing tool is as follows:

The universal support 3 is set at a height for allowing the truing tool to be freely slid in position with the protrusions 10′ engaging the leg 3′ of the universal support 3. The yoke 10 is locked in position by the fastening screw 11.

The machine is started, and the universal support 3 is lowered by means of the adjustment nut 3″, until the cutting tip 13 touches the highest spot on the grindstone 1.

After stopping the machine, the holder 12 with the cutting tip 13 is transferred outside the grindstone 1 by the operating knobs 15. The desired cutting depth for the cutting tip 13 is set by means of the adjustment nut 3″. The maximum cutting depth may be 0.8 mm.

The machine is again started, and the cutting tip 13 is transversely fed over the rotating grindstone 1 in both directions by means of the operating knobs 15. It is suggested to use 1.5-2 minutes for moving across the grindstone 1.

A comparison between the known truing tool according to FIG. 1 and the new truing tool according to FIGS. 2-4 gives the following result:

The transverse feeding in the new tool occurs by turning operating knobs 15, whereas a manual handling of the tool holder 5 is necessary in the old tool.

For the new tool, the cutting depth is set with high precision by means of the adjustment nut 3″, whereas the cutting depth in the old tool is set manually by means of the position of the U-rod 2 on the universal support 3.

The new tool is in one piece and may easily be mounted, whereas the old tool is in two pieces. 

1. A truing tool for a grindstone (1), the tool being intended for attachment to a universal support (3) in the form of a cylindrical rod of a grinding machine in parallel with the rotation axis of the grindstone and having—in a holder (12) therefore slidingly arranged on the universal support—a cutting tip (13) for truing engagement with the grindstone, characterized in that the holder (12) is movably connected to a yoke (10)—which is attached to the universal support (3)—by a threaded feeding rod (14), which is rotatably supported by the yoke (10) and is in engagement with a threaded bore in the holder (12), for its movement in relation to the yoke transversely of the grindstone (1).
 2. A truing tool according to claim 1, wherein the feeding rod (14) is provided with operating knobs (15) at its ends outside the yoke (10).
 3. A truing tool according to claim 1, wherein the holder (12) has a transverse hole for its movable connection to the universal support (3).
 4. A truing tool according to claim 1, wherein the cutting depth for the cutting tip (13) is set by fine adjusting the height of the universal support (3) over the grindstone (1). 